1. Field of the Invention
The present invention relates to boehmite aluminas, more particularly to modified boehmite aluminas that are dispersible in polar organic and/or aqueous media.
2. Description of the Prior Art
Thickened or viscous compositions containing aqueous solutions and/or polar organic liquids have utility in a wide variety of applications. For example, such thickened compositions can be used as coating removers to remove paint, varnish, and similar coatings from surfaces; graffiti removers; deicers for use on aircraft; etc. Typically, the thickened organic-liquid-containing compositions necessarily contain, in addition to water, the desired water miscible (soluble) organic liquid and a thickening additive that imparts the desired rheological properties to the composition. One thickener that has been widely used for water/polar organic solvents is boehmite alumina. Depending on how it is treated, boehmite alumina is dispersible in water and aqueous solutions containing polar, miscible organic liquids. However, boehmite alumina is generally not dispersible in anhydrous mixtures or solutions of polar organic liquids.
There are instances when it would be desirable to prepare a thickened or viscous polar organic liquid that did not contain water. For example, in the deicing of aircraft, the glycols that are used drain to sumps from which the spent glycol can be recovered and reclaimed so as to be reusable. Obviously, the presence of large amounts of water in the glycols increases the costs of reclaiming the glycol. Additionally, there are instances in which the presence of water may lessen the effectiveness of the polar organic liquid, e.g., in certain cleaning applications. Clearly, it would be desirable to have a boehmite alumina that is dispersible not only in water, but also in polar organic liquids essentially free of water.